Pneumatic tires and, in particular when used off-the-road, typically collect mud and dirt on the sidewall, as well as the lettering on the tire. This results in an unsightly tire. The purpose of the present invention is to reduce the amount of dirt which adheres to the sidewall and lettering by applying a coating of a fluorinated silane over the existing tire sidewall. The coating provides an automatic cleaning effect decreasing the need for scrubbing the sidewall.
Pneumatic tires also collect water in the tread grooves. The purpose of the present invention is also to reduce the adhesion of water and mud inside the grooves, by applying a coating of fluorinated silane to the groove walls, thus obtaining a better evacuation of water as well as a self-cleaning effect.
A clean and dry tire also reduces the weight of the tires as well as the air resistance, thus reducing the fuel consumption. Efforts to reduce air resistance of objects in motion in order to achieve a reduction in fuel consumption have been disclosed for surfaces such as the metallic surface of an airplane. For example, U.S. Pat. No. 4,865,271 by Savill teaches to provide an aerodynamic or hydrodynamic surface with so-called “riblets” for reducing drag by modification of the turbulent boundary layer, which is the thin layer of air molecules that touches the surface of the object and causes friction. The riblets comprise flow-aligned elongate projections of small height.
U.S. Pat. No. 4,706,910 by Walsh et al. discloses a system of flow control devices which result in reduced skin friction on aerodynamic surfaces. The devices cause a breakup of large-scale disturbances in the boundary layer of the flow field by the use of longitudinal striations forming V-shaped grooves.
Against this background, it is an object of the present invention to provide rubber tires that have an improved dirt-repellence whereby the weight of the tire and, consequently the air resistance, are reduced and savings in fuel consumption are obtained.
It is another object of the invention to provide tires having a self-cleaning effect and permitting a reduction of cleaning material to be used.